Computer history LEOK: Period 1964 - 1974

LEOK's own computer centre

At the end of the sixties, LEOK started to reserve funds to buy a computer system
for a new to establish computer centre as part of the Laboratorium Elektronische
Ontwikkelingen Krijgsmacht (LEOK). The primary
objective was to buy a process-control computer. At the same time, the computer
system had to be equipped with enough software and input/output equipment to support
program development and scientific research purposes. After market analysis, a
system configuration based upon the Ferranti FM 1600B-computer was recommended
on grounds of price, delivery time and quality of the instruction set and organisation
of the input/output.

The contract was placed end of 1969 (after some delays), causing a
computerless-period between the end of the 3D-simulator project in 1970
and the acceptance of the Ferranti FM 1600B system.

In the mean time, limited spare capacity of the SIMREK
system of the Royal Netherlands Navy in Den Helder could be used. Thus, the
newly Computation/programming group (Rekenafdeling/programmeergroep) had to
limit their activities to the preparation of the installation of LEOK's own
Ferranti FM1600B computer. Fortunately, the RAREK
computer became available earlier than expected as the 3D-project ended and
the system was made available to the LEOK.

Ferranti FM1600B computer

Ferranti computer
(photo's made during the conveyance of the system)
Click thumbnail for enlarged photo

In the summer of 1971, LEOK's own Ferranti FM1600B
was accepted. The photo's above, made during the conveyance of the system, give
an impression of the total system and the input/output equipment.

The software comprised compilers for
ALGOL
60, FORTRAN II and CORAL 64, a FIXPAC asembler, a subroutine library and
utilities. CORAL 64 was at that time the NATO programming standaard, block structurered
as Algol 60, for applications in real-time environments. The compiler had six
passes! Calculations could be performed in integer, floating point, or fixed
point (where the comma moved around). The advantage was an optimum precision
and maximum speed.
FIXPAC (FixedPoint Autocode) was the assembler. Instructies were based on three
adresses, e.g., Va=Vb+Vc - V was written as the Greek character 'nu').

Programs were started from papertape.
During compilation of a program, multiple passes of the compilation process
resulted in intermediate code on papertape. The computer was controlled from
the operator panel. We developed our own operating system that allowed the use
of magnetic tape. After these modifications the de bootstrap recognised the
magnetic tape drive as a "boot device". We called that "BOS".
Later on, a larger operating system "EOS" was loaded from magnetic
tape . It had a simple command structure and a very universal IO-interface.
A own-developed text editor, like the one on a PDP 8 was added. Compilers were
disassembled and adapted to make use of the IO-interface("I
recal that my collegue Pim O. worked hard for several months to get the Algol
compiler working. Finally, it produced an "Eureka" stating "It
is ok now, boys"). A Tektronix phosphorus memory screen was used
as operator station. Finally the noisy Teletype could be switched off. The operasting
system was sold to Ferranti for an extra block of memory. EOS was used, with
disk instead of magnetic tape, for the Mechlua trainer project

An important project which used the Ferranti was Torpeval (2D-phase). Information
recorded at ships of the Royal Netherlands Navy was processed by the LEOK. The
outcome was presented in the form of tables and plots. Printing and plotting
of the Torpeval results required the writing of Torpeval in assembly code. Later,
LEOK changed the ALGOL
and FORTRAN compiIers/runtime systems in such a way that the output devices
could be addressed in a more high-level way causing programming to become quicker
and easier.

The hardware was extended with the needed core memory till 32K (total) and
a display-terminal.

The Ferranti system was used for:

Processing measurement data recorded at location (e.g. calibration corrections
for the submarines and mine hunting)

End of 1969, a 2400 baud synchronous terminal connection was made with the
Control Data CDC 6400 of the Physics
Laboratory RVO-TNO. Two TNO-collegues of the Prins Maurits Laboratory had
implemented that code in Basic Plus, the standard language for the DEC Resource
Time Sharing System or RSTS/E operating system on PDP-11's. Basic Plus was a
completely unstructurered Basic derivative. It had statement modifiers: additional
clauses placed at the end of a Basic statement. The kick was to write your program
in only a limited number of statements, with one command spanning to more than
half a page. At the same time, plans were developed to couple the RAREK to the
CDC 6400 and to fit the Ferranti FM1600B
with a time-sharing operating multi-user system. However, before these plans
were realised, the Ferranti was replaced by a DIGITAL PDP
11/60. This configuration was extended later with a DIGITAL PDP 11/44 and
a PDP
11/34.

The largest project of the LEOK during that period was the Mech
Lua (Luchtafweer = Anti-air) Trainer (MLT) based on
Ferranti FM1600B computers. These trainers are still (1998!) in use in Ede (they
are 'retired' now). One of the TNO-FEL employees concluded in the beginning
of 1998: "It is remarkable to see such a system still working, it even does
not make a worn-out impression!"

Anecdote: Navy-blue papertape

An important LEOK project required the processing of measurements recorded in
many hundreds of meters of papertape. The measurements were made on board
of Royal Netherlands Navy ships. The problem was that the
Ferranti had an "ultra modern" papertape reader which used light cells.
Our Royal Netherlands Navy
used mechanical papertape equipment and "cheap" white (uncolored) papertape.
The light cells of the Ferranti papertape reader were extremely sensitive,
causing "read-through" the Navy white papertape. In short, all "bit positions"
were read as "holes".
Copying would be a tedious task and could introduce
errors (given the reliability of equipment at that time). Secondly,
LEOK possessed no papertape duplication equipment. Thus, one single
option was left: coloring the papertape.
Several bottles of ink were emptied in a wastepaperbasket.
The papertapes were then slowly transported through the ink. After
drying of the now (Navy)-blue papertape, the measurement data could be processed
flawlessly.